The Islamic conception of hell is similar to the Christian conception of hell: Muslim hell is called Jahannam and it is a place of fire and torture. Deceased sinners enter through one of seven gates, according to the nature of their sins, and are given clothing made of fire (which sounds like it would be hard to dry-clean). The souls are mercilessly burned until they become black like charcoal. Nineteen angels oversee the administration of fire-based torture.
But Jahannam does have a special garden feature lacking from Christian hell. In the middle of the fiery realm is a great malevolent tree named Zaqqum with roots that snake down into the raging fires beneath the world. Zaqqum has fruits which are shaped like devil’s heads. The hungry spirits trapped in hell eat these fruits, which are the only foodstuff to be had, but the fruits only intensify the suffering of the damned. The Quran directly mentions the pain caused by eating Zaqqum’s fruit:
[44.43] Indeed, the tree of zaqqum
[44.44] Is food for the sinful.
[44.45] Like murky oil, it boils within bellies
[44.46] Like the boiling of scalding water.
Other references compare eating the fruit of Zuqqum to swallowing boiling brass, or relate how consuming the fruit is so painful that it causes the eaters’ faces to fall off!
There are no known allusions to Zuqqum before Mohammed. The concept originated with his revelations. Since the writing of the Quran, a number of thorny, poisonous, or bitter trees from Muslim lands have derived their common name from Zuqqum the great misery tree of Jahannam which feeds directly on the fires of hell.